Welding on a fuel tank

[david58]

Here are two threads on welding gas tanks.
http://www.shoptalkforums.com/viewtopic ... 998#796998

[Leatherneck]

We welded up a S/B tank, just made sure that is was completely dry after being purged with water and blown out. Common sense is required,thinking it through is required, safety is required but welding a gas tank is very doable.

[adaze1]

I have welded more fuel tanks then I can count. I have filled them with water, yes they still go boom. Wash them out real good then place wet rags over the openings. Just rember when they do light up they will only do it once. its actualy prity cool once your heart beat slows down. Keep a fir ext close by. I poped a 22 gal tank from a ford van the filler neck looked like a jet engine. Every one in the shop was gone buy the time I looked up. I never even had time to use the ext that was next to me. I told the boss hell no i'm not welding any more tanks. He tells me it will only burn once. keep going. I

[fastvwman]

I have welded tanks filled with water with no problem. water doesnt explode. how did you manage to do that?

[Bugfuel]

Rinsing won't help, you have to LEAVE the water in there!!

Its job is to take up the space that would otherwise be filled with fumes.

You can safely have a flame burning at any opening of the tank, but what you do NOT want is an air pocket that goes inside the tank. The best way to eliminate the possibility alltogether is to fill the space with something else - water works great!

Jan

[fastvwman]

exactly, fill it up and leave it in!

[berniedd]

Even after a week of drying, dangerous gas molecules still remain in the pores of the metal of the tank! To get around this,I put 7 liters of water with soapy detergent in the tank and slosh it around real good. The detergent soaks up the gas,and I can weld safely thereafter. Note that that water is not supposed to be drained while welding is ongoing.

[Super "B"]

After washing out the tank with water. Take your gas tank and put the inlet of it on a exhaust pipe of a running car. This will fill the tank with Carbon dixocides . after doing that for about 15 minutes you can place a lighted match or torch head into the tank. If anything you may here a small boom. The less oxygen in the tank the less change of a flame up. From there you can start welding. I have tried this twice so far at it has worked great while welding fuel sumps on tanks for drag cars.....But as always be careful and keep a fire extinguisher handy....

[INSAYN]

How about dry ice and hot water to get the dry ice to smoke? Again, it's only carbon dioxide.

[bug65]

if i had to weld a tank i would definitely use the exhaust technique, and keep the exhaust running while welding. keep the oxygen content inside of the tank to a minimum. use caution.
jd

[turbowd57rag]

[quote="Super "B""]After washing out the tank with water. Take your gas tank and put the inlet of it on a exhaust pipe of a running car. This will fill the tank with Carbon dixocides . after doing that for about 15 minutes you can place a lighted match or torch head into the tank. If anything you may here a small boom. The less oxygen in the tank the less change of a flame up. From there you can start welding. I have tried this twice so far at it has worked great while welding fuel sumps on tanks for drag cars.....But as always be careful and keep a fire extinguisher handy....[/quote]

I have been doing it this way for years....never a flare up. It works

Pete

[class5]

i used to weld alum tanks from aircraft to boats to what ever .some tanks you just cant put water in so you purg them with argon .wellllllll i made one mistake one day and boom a 40 gallon alum tank blew and when it did it blew the end cap out and the baffel it sent the tank of the bench into the parking lot about a 100 feet .broke my fingers ,my nose, from the end cap blew every window out of building ,the end cap hit the bottel regulator and sheard it right off .the heat blew the sleaves of my shirt and the concusion from the blast made me numb .i thought i was dead i couldent hear or feel anything .the glass from my hood was buried in my fourhead and bleeding about as bad as my nose . that was the last tank i ever did theres not enuff money that you could pay me to weld one because your day will come and hopefully you get lucky like i did .and i dont care how good you think you are the odds will get ya .and to top things off it was the day after the oaklahoma bombings i had ever fed ,state and city inspector and investeagters at my place wanting to know just what the hell i was up to lol.

[perrib]

I have welded fuel tanks by letting the exhaust from my 454 heat the tank until its to hot to hold after I rinse them with water. All of the fumes evaporate. I am counting on the heat to remove the fuel not the carbon dioxide to keep it from burning. Several old school craftsman showed me this technique. Most of the time I solder a penny over the leak after I sand blast the rust. I use an old school soldering iron that I heat with the torch. Along with class five and others who have had a tank explode, I can not reccomend this method. No fire department will agree with this technique. Due to the explosive nature of fuel it would be safer to have a radiator shop clean the tank. Like Richard Pryor said you have no friends while you are on fire. On the Hotrodders.com forum there is a post about someones friend being killed while welding a fuel tank using exhaust fumes to displace the air.

[AirCool]

Haven't any of you tried filling the tank with shield gas? No oxygen = no bang. Rinse it with hot soapy water first still, but it works. If you have CO2 to fill it with it also works OK.

[The Newf]

Nitrogen.